JPH10309682A - Driving shaft structure of robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving shaft structure of a robot, capable of easily changing a ball screw and a screw cover. SOLUTION: A ball screw unit 53 is constituted by integrally providing a ball screw 54 provided with a screw shaft and a nut 54b to be screwed to this screw shaft, ball bearings 56, 62 on the upper and lower ends of the screw shaft, for rotatably supporting the screw shaft, a gear 68 provided on the lower end of the screw shaft in order to transmit driving force of a motor 74 to the screw shaft, and screw covers 69, 70 respectively provided between the nut 54b and the ball bearing 56 and between the nut 54b and the ball bearing 62. The ball screw unit 53 can be drawn out upward (in the axial direction of the screw shaft) from a support 52 by detaching a bolt 60 fixing the ball bearing 56 to the upper frame 61 of the support 52, a bolt 75 connecting the nut 54b and a slide base 66 (a horizontal arm), and a bolt 64 fixing the ball bearing 62 to a lower frame 65 of the support 52.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive shaft structure for a robot, and more particularly, to a linear movement having a ball screw on one axis, such as a horizontal articulated palletizing robot used for palletizing boxes and bags. This is useful when applied to a horizontal articulated robot that is an axis.

[0002]

2. Description of the Related Art FIG. 5A is a side view of a conventional horizontal articulated robot, FIG. 5B is a front view of the horizontal articulated robot, and FIG. 6 is a structural diagram of one axis of the horizontal articulated robot. It is.

As shown in FIG. 5, the horizontal articulated robot 1 has a single axis 6 which moves linearly in the vertical direction as indicated by an arrow A.
In addition, a horizontal arm 10 having two axes 7, 3 axes 8, and 4 axes 9 that rotate horizontally as indicated by arrows B, C, and D is attached thereto. The one shaft 6 is provided in the hollow support 2, and includes a ball screw 4 including a screw shaft 4 a rotatably supported by the support 2 and a nut 4 b screwed to the screw shaft 4 a, and a screw shaft 4 a And a motor 3 for rotationally driving the motor.

[0006] More specifically, as shown in FIG. 6, a ball screw 4 is provided upright in a column 2, and a flange 5 fixed to an outer peripheral side of a nut 4 b of the ball screw 4, a slide base 19, Are connected by bolts 20.
The horizontal arm 1 is attached to the slide base 19.
0 (see FIG. 5) are combined.

Further, ball bearings 11 and 12 are fixed to the upper end and the lower end of the screw shaft 4a of the ball screw 4, respectively. A flange 13 is fixed to the outer peripheral side of the upper ball bearing 11.
Are fixed to the upper pedestal (upper surface) 14 of the column 2 by bolts 15. On the other hand, a flange 16 is fixed to the outer peripheral side of the lower ball bearing 12.
6 is mounted on a lower frame 17 of the column 2 and fixed by bolts 18. The support 2 is composed of an upper part 2a and a lower part 2b, and the upper part 2a and the lower part 2b are
Are joined by

The motor 3 is disposed below the screw shaft 4a of the ball screw 4, and the screw shaft 4a and the rotating shaft 3 of the motor 3
a is connected by tightening the bearing nut 22.

Therefore, one axis 6 of this horizontal articulated robot
By rotating the screw shaft 4a of the ball screw 4 by the motor 3, the slide base 19 (that is, the horizontal arm 10) moves linearly in the vertical direction together with the nut 4b.

[0008]

Since the single shaft 6 of the above-mentioned horizontal articulated robot 1 uses the ball screw 4 which uses a ball as a rolling element similarly to a ball bearing,
The ball screw 4 has a life due to abrasion of the ball or the like in accordance with the number of rotations of the ball screw 4 and the load applied to the ball screw 4. Therefore, at the time of periodic inspection, the presence or absence of grease on the ball screw 4
It is necessary to determine the replacement time of the ball screw 4 by checking the surface condition and the presence or absence of abnormal noise or vibration during the rotation operation, and to replace the ball screw 4 at this time. Further, the ball screw 4 may be damaged at an unexpected time, and the ball screw 4 must be replaced at this time.

However, in order to remove the ball screw 4 from the column 2 and replace it, the bolt 15 for fixing the upper ball bearing 11 to the upper base 14, the nut 4b of the ball screw 4 and the slide base 19 (ie, the horizontal arm) 10)
In addition to removing the bolt 20 connecting the lower ball bearing 12 and the bolt 18 that fixes the lower ball bearing 12 to the lower pedestal 17, the bearing nut 22 is further loosened to remove the screw shaft 4a of the ball screw 4. After separating the rotating shaft 3a of the motor 3 and removing the bolt 21 to separate the upper part 2a and the lower part 2b of the column 2, the upper part 2a must be removed with a large lifting machine.

Therefore, the replacement of the ball screw 4 takes a considerable amount of time and labor, and the replacement of the ball screw 4 and the re-assembly also take a lot of time. Was taking a long time.

Further, when the horizontal articulated robot 1 is installed and used in a place where there is a lot of dust, the ball screw 4 is liable to break down due to the dust. However, when replacing the screw cover, the ball screw 4 had to be removed in the same manner as described above. Moreover, since the screw cover is a semi-consumable item, it needs to be replaced more frequently than the ball screw 4,
The labor and time required for the replacement work are enormous.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a drive shaft structure of a robot which can easily replace a ball screw and a screw cover in view of the above-mentioned prior art.

[0013]

Means for Solving the Problems A first method for solving the above problems is described below.
The drive shaft structure of the robot according to the invention includes a ball screw including a screw shaft and a nut screwed to the screw shaft, and a first shaft rotatably supporting the screw shaft at both ends of the screw shaft. A ball screw unit is integrally provided with a bearing, a second bearing, and a gear provided on the screw shaft for transmitting the driving force of the motor to the screw shaft. (1) a bolt fixing the support portion, a bolt connecting the nut to another drive shaft of the robot, and a bolt fixing the second bearing to the second support portion on the support side. By removing the ball screw unit, the ball screw unit can be pulled out from the support side in the axial direction of the screw shaft.

According to a second aspect of the present invention, there is provided a drive shaft structure for a robot, comprising: a ball screw having a screw shaft and a nut screwed to the screw shaft; and rotating the screw shaft at both ends of the screw shaft. A first bearing and a second bearing that can be supported, a gear provided on the screw shaft for transmitting a driving force of a motor to the screw shaft, a gap between the nut and the first bearing, and a gap between the nut and the first bearing. Forming a ball screw unit integrally provided with a first screw cover and a second screw cover provided between the second screw cover and the second bearing;
A bolt for fixing the first bearing to the first support portion on the support side, a bolt for connecting the nut to another drive shaft of the robot, and a second support for the second bearing on the support side. The ball screw unit can be pulled out in the axial direction of the screw shaft from the support side by removing a bolt fixed to the portion.

Therefore, according to the drive shaft structure of the robot of the first or second aspect, the first bearing is provided on the first side of the support side.
A bolt fixed to the support portion, a bolt connecting the nut of the ball screw and another drive shaft of the robot,
By removing the bolt fixing the bearing to the second support portion on the support side, the ball screw unit can be pulled out from the support side in the axial direction of the screw shaft and easily removed.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a structural diagram of one axis of a horizontal articulated robot according to an embodiment of the present invention, FIG. 2 is a sectional view taken along the line FF of FIG. 1, and FIG. 3 is a line GG of FIG. FIG. 4 is a cross-sectional view of FIG.
FIG. 4 is an explanatory diagram showing a state when the single-axis ball screw unit shown in FIG.

The horizontal articulated robot 51 shown in FIG. 1 has a ball screw unit 53 that moves linearly in the vertical direction as indicated by an arrow H as one axis, and the single-axis ball screw unit 53 rotates horizontally. A horizontal arm (not shown) having a plurality of drive shafts (see horizontal arm 10 in FIG. 5) is attached. And ball screw unit 53
Are ball screws 54, ball bearings 56 and 62,
The gear 68 and the screw covers 69 and 70 are integrally provided.

More specifically, referring to FIGS. 1, 2 and 3, a ball screw 54 comprising a screw shaft 54a and a nut 54b screwed to the screw shaft 54a is provided upright in the column 52. The nut 54b of the ball screw 54 is removably inserted into a through hole 66a of a base end portion 66b of the slide base 66, and a flange 76 is fixed to an outer peripheral side thereof by a bolt 67.
6 and the base end 66b of the slide base 66 are bolts 75
Are joined by The horizontal arm is attached to the slide base 66. That is,
Nut 54b of ball screw 54 and slide base 66
(That is, the horizontal arm) are connected by bolts 75.

A ball bearing 56 is fixed to the upper end of the screw shaft 54a of the ball screw 54, and a flange 57 is fixed to the outer periphery of the ball bearing 56. A flange 59 a at the lower end of a cylindrical support member 59 is fixed to the flange 57 by a bolt 58. The upper end of the support member 59 penetrates through the through-hole 61 a of the upper mount (upper surface) 61 of the column 52, and the flange 59 b of the upper end is placed on the upper mount 61 and the bolt 60
Has been fixed by. That is, the upper ball bearing 56 is fixed to the upper base 61 by the bolts 60 via the support members 59.

On the other hand, a ball bearing 62 is fixed to the lower end of the screw shaft 54a.
The flange 63 is fixed to the outer peripheral side of. Then, the flange 63 is placed on the lower frame 65 of the support 52 and the bolt 6
4 fixed. That is, the lower ball bearing 62 is fixed to the lower base 65 by the bolt 64. A gear 68 is fixed to the lower end of the screw shaft 54a.

The gear 68 meshes with a first intermediate gear 71 rotatably provided at the lower end of the column 52, and the first intermediate gear 71 is rotatable with a second intermediate gear 71 provided at the lower end of the column 52.
The second intermediate gear 72 meshes with a gear 73 fixed to a rotating shaft 74 a of a motor 74 that is disposed downward on the side of the ball screw unit 53. That is, the screw shaft 54a of the ball screw 54 is connected to the gears 68, 71,
It is connected to a rotating shaft 74 a of a motor 74 via 72 and 73.

Therefore, the rotational force of the rotating shaft 74a of the motor 74 is transmitted to the ball screw 54 via the gears 68, 71, 72, 73.
Is transmitted to the screw shaft 54a of the
4a rotates, and the nut 54b moves linearly in the vertical direction together with the slide base 66 (that is, the horizontal arm). Note that a stopper 77 is provided below the slide base 66, and the lower end surface of the slide base 66 comes into contact with the stopper 77 when the slide base 66 is lowered to the lower end of its stroke.

Screw covers 69 and 70 are provided between the nut 54b of the ball screw 54 and the upper ball bearing 56 and between the nut 54b and the lower ball bearing 62, respectively. These screw covers 69 and 70 are configured so as to be able to expand and contract in accordance with the vertical movement of the nut 54b, and to prevent dust from adhering to the ball screw 54 around the screw shaft 54a. Preventing.

Moreover, the through holes 6 in the upper mount 61 of the support 52
1a inserts the through holes 61a into the ball bearings 56, 62.
Flanges 57 and 63 and ball nut 55 flange 7
6 is large enough to pass through, and the slide base 6
The through hole 66a of the base end portion 66b of the No. 6 has such a size that the flange 63 of the ball bearing 62 can pass through the through hole 66a. That is, the ball screw unit 53 can be vertically inserted and removed through the through hole 61a of the upper gantry 61 and the through hole 66a of the slide base 66.

Therefore, one of the horizontal articulated robots 51
In the structure of the shaft, the ball screw 54 or the screw cover 6
When performing replacement or maintenance of 9, 70, the ball screw unit 53 is taken out of the support 52 by the following procedures (1) to (4).

First, the screw shaft 54 a of the ball screw 54 is rotationally driven by the motor 74, so that the nut 54 b
At the same time, the slide base 66 is moved downward to come into contact with the stopper 77.

In this state, the bolt 7 connecting the nut 54 b of the ball screw 54 and the slide base 66
Remove 5 Further, the bolts 60 fixing the upper ball bearing 56 to the upper mount 61 are removed, and the bolts 64 fixing the lower ball bearing 62 to the lower mount 65 are also removed.

As a result, the ball screw unit 5
The eye bolt (not shown) is attached to the flange 59b of the support member 59 because the support member 3 is free with respect to the support post 52.
A rope is hung on this eyebolt and the ball screw unit 5
3 is lifted upward (that is, in the axial direction of the screw shaft 54a). The state at this time is shown in FIG. Thus, the ball screw unit 53 is taken out of the column 52,
It can be easily disassembled into individual parts outside.

As described above, according to the uniaxial structure of the horizontal articulated robot 51 according to the present embodiment, the bolts 60 fixing the upper ball bearing 56 to the upper base 61 are used.
, Nut 54b of ball screw 54 and slide base 6
6 (ie, a horizontal arm),
The ball screw unit 53 can be easily removed by pulling out the ball screw unit 53 from the column 52 in the axial direction of the screw shaft 54a simply by removing the bolt 64 fixing the lower ball bearing 62 to the lower mount 65. Of course, it is also easy to reinsert the ball screw unit 53 into the support post 52 and perform reassembly after replacing or maintaining the ball screw 54 and the screw covers 69 and 70.

That is, the bearing nut 22 is loosened to separate the screw shaft 4a of the ball screw 4 from the rotating shaft 3a of the motor 3 as in the prior art (see FIG. 6). There is no need to separate the lower part 2b from the upper part 2b and remove the upper part 2a with a large lifting machine, and no special jig is required.

Therefore, replacement work and maintenance work of the ball screw 54 and the screw covers 69 and 70 can be easily performed in a short time. In addition, since the replacement work and the maintenance work can be easily performed in a short time in this manner, the component replacement work and the maintenance work can be performed early (frequently), so that the reliability is improved. You can also.

[0033]

As described above in detail with the embodiments of the present invention, according to the drive shaft structure of the robot of the first or second aspect of the invention, the bearing nut is loosened and the There is no need to separate the screw shaft from the motor shaft, remove the bolts to separate the upper and lower parts of the column, and remove the upper part with a large lifting machine. A bolt that fixes the first bearing to the first support portion on the support side, a bolt that connects a nut of the ball screw to another drive shaft of the robot,
By removing the bolt that fixes the second bearing to the second support portion on the support side, the ball screw unit can be easily pulled out from the support side by pulling it out in the axial direction of the ball screw. Of course, it is also possible to easily reinsert the ball screw unit into the support side after the replacement or maintenance of the ball screw or the screw cover, and perform reassembly.

Therefore, the replacement work and maintenance work of the ball screw and the screw cover can be easily performed in a short time. In addition, since the replacement work and the maintenance work can be easily performed in a short time in this manner, the component replacement work and the maintenance work can be performed early (frequently), so that the reliability is improved. You can also.

[Brief description of the drawings]

FIG. 1 is a structural diagram of one axis of a horizontal articulated robot according to an embodiment of the present invention.

FIG. 2 is a sectional view taken on line FF of FIG. 1;

FIG. 3 is a sectional view taken along line GG of FIG. 1;

FIG. 4 is an explanatory diagram showing a state when the uniaxial ball screw unit shown in FIG. 1 is pulled out.

FIG. 5A is a side view of a conventional horizontal articulated robot,
(B) is a front view of the horizontal articulated robot.

FIG. 6 is a structural diagram of one axis of the horizontal articulated robot.

[Explanation of symbols]

 51 Horizontal Articulated Robot 52 Support 53 Ball Screw Unit 54 Ball Screw 54a Screw Shaft 54b Nut 56,62 Ball Bearing 57,59a, 59b, 63,76 Flange 58,60,64,67,75 Bolt 59 Supporting Member 61 Upper Stand 61a through hole 65 lower mount 66 slide base 66a through hole 66b base end 68, 73 gear 71 first intermediate gear 72 second intermediate gear 74 motor 74a rotating shaft 77 stopper

Claims (2)

[Claims] 1. A ball screw comprising a screw shaft and a nut screwed onto the screw shaft, and first and second bearings at both ends of the screw shaft for rotatably supporting the screw shaft. And a gear provided on the screw shaft for transmitting the driving force of the motor to the screw shaft to form a ball screw unit, and the first bearing is fixed to the first support portion on the support side. The ball is removed by removing the bolt that is connecting the nut, the bolt that connects the nut to the other drive shaft of the robot, and the bolt that fixes the second bearing to the second support on the support side. A drive shaft structure for a robot, wherein the screw unit can be pulled out from the support side in the axial direction of the screw shaft. 2. A ball screw comprising a screw shaft and a nut screwed to the screw shaft, and first and second bearings at both ends of the screw shaft for rotatably supporting the screw shaft. A gear provided on the screw shaft for transmitting the driving force of the motor to the screw shaft; and a first gear provided between the nut and the first bearing and between the nut and the second bearing. A ball screw unit integrally comprising a screw cover and a second screw cover, a bolt fixing the first bearing to the first support portion on the support side, the nut and another drive shaft of the robot The ball screw unit is removed from the support side in the axial direction of the screw shaft by removing a bolt connecting the ball screw unit and a bolt fixing the second bearing to the second support portion on the support side. A drive shaft structure for a robot, which can be pulled out.